Light emitting device

ABSTRACT

A light emitting device includes one or more electrical components and a base member. The electrical components include a first semiconductor laser element, which has a light emission end surface. The base member has a first surface on which the first semiconductor laser element is disposed. The base member includes a plurality of metal films including a first metal film and a second metal film. The first metal film is electrically connected to at least one of the electrical components, and defines a first alignment mark for aligning the first semiconductor laser element. The second metal film is electrically connected to at least one of the electrical components, and defines a second alignment mark for aligning the first semiconductor laser element. A straight line connecting the first alignment mark and the second alignment mark extends parallel to the light emission end surface of the first semiconductor laser element.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 16/791,791, filed on Feb. 14, 2020. Thisapplication claims priority to Japanese Patent Application No.2019-025299, filed on Feb. 15, 2019, and Japanese Patent Application No.2019-172444, filed on Sep. 24, 2019. The entire disclosures of U.S.patent application Ser. No. 16/791,791, and Japanese Patent ApplicationNos. 2019-025299 and 2019-172444 are hereby incorporated herein byreference.

BACKGROUND 1. Technical Field

The present disclosure relates to a method of manufacturing a lightemitting device, a light emitting device, and a base member adapted tobe installed in the light emitting device.

2. Description of Related Art

There has been a known method in which an element such as a lightemitting element is mounted on a mount surface according to an alignmentmark formed on the mount surface. For example, JP 2012-164737 Adescribes a submount in which an alignment mark is formed on a firstsurface, where a semiconductor light emitting element is to be mounted,of the submount.

SUMMARY

In JP 2012-164737 A, only the mounting precision of a singlesemiconductor light emitting element, which is an element mounted on themount surface, is considered. Meanwhile, when a plurality of elementsare mounted on a single mount surface in an optical system,configuration for improving the mounting precision is required in acomprehensive standpoint.

A light emitting device according to the present disclosure includes oneor more electrical components and a base member. The one or moreelectrical components include a first semiconductor laser element. Thefirst semiconductor laser element has a light emission end surface. Thebase member has a first surface on which the first semiconductor laserelement is disposed. The base member includes a plurality of metal filmsincluding a first metal film and a second metal film. The first metalfilm is electrically connected to at least one of the one or moreelectrical components, and defines a first alignment mark for aligningthe first semiconductor laser element. The second metal film iselectrically connected to at least one of the one or more electricalcomponents, and defines a second alignment mark for aligning the firstsemiconductor laser element. A straight line connecting the firstalignment mark and the second alignment mark extends parallel to thelight emission end surface of the first semiconductor laser element.

The present disclosure allows a light emitting device to be preciselymounted. The present disclosure also allows for obtaining a lightemitting device which can be precisely mounted. The present disclosurealso allows for obtaining a base member that allows precise mounting.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view of a light emitting deviceaccording to a first embodiment.

FIG. 2 is a schematic top view of the light emitting device shown inFIG. 1.

FIG. 3 is a schematic cross-sectional view of the light emitting devicetaken along line III-III in FIG. 2.

FIG. 4 is a schematic perspective view for describing the internalconfiguration of the light emitting device according to the firstembodiment.

FIG. 5 is a schematic top view corresponding to FIG. 4.

FIG. 6 is a schematic perspective view for describing the internalconfiguration of the light emitting device according to the firstembodiment.

FIG. 7 is a schematic top view corresponding to FIG. 6.

FIG. 8 is an enlarged partial schematic top view of an upward-facingsurface (a disposition surface) of a base member with reference to FIG.7.

FIG. 9 is a schematic perspective view of a light-transmissive memberand a wavelength conversion member bonded to each other according to thefirst embodiment.

FIG. 10 is a schematic top view corresponding to FIG. 9.

FIG. 11 is a schematic top view in which the wavelength conversionmember is shown in a transparent manner for describing the bondingsurface between the light-transmissive member and the wavelengthconversion member according to the first embodiment.

FIG. 12 is a schematic bottom view of the wavelength conversion memberaccording to the first embodiment.

FIG. 13 is a schematic perspective view of a light emitting deviceaccording to a second embodiment.

FIG. 14 is a schematic top view of the light emitting device shown inFIG. 13.

FIG. 15 is a schematic perspective view for describing the internalconfiguration of the light emitting device according to the secondembodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

In the description and the claims, the term “polygonal shape”encompasses polygonal shapes such as triangular shapes, quadrangularshapes, and the like with modified corners such as rounded corners,truncated corners, etc. The term “polygonal shape” also encompassespolygonal shapes with modification at intermediate portions of sides ofthe polygonal shapes (i.e., portions other than ends of sides of thepolygonal corners). That is, a polygonal shape with modification isconstrued as “a polygon” recited in the description and claims.

Similarly, other terms indicating specific shapes, such as a circle, arecess, a projection, etc., encompasses respective shapes withmodification. This is similar for each side forming such a shape. Thatis, a side having ends with modification and/or an intermediate portionwith modification is construed as “a side”. When indicating “a polygonalshape” or “a side” without intended modification separately from amodified “polygonal shape” or a modified “side”, such shapes withoutintended modification are referred to with the term “exact”, such as “anexact quadrangle”.

In the description and claims, when a plurality of elements correspondsto a single constituent and are to be indicated separately from eachother, the term of such elements are referred to with the words “first”,“second”, etc. Such indication of elements with the words “first”.“second”, etc., for indicating the elements corresponding to a singleconstituent separately from each other may be different between thedescription and claims, when the elements to be indicated as “first”,“second”, etc., or the view of separation between “first”, “second”,etc., is different between the description and claims.

With reference to the drawings, certain embodiments of the presentinvention will be described below. Embodiments described below areintended to give a concrete form to the technical idea of the presentinvention, and are not intended to limit the scope of the presentinvention. In the description below, identical names and identicalreference numerals indicate identical or similar members, and repetitivedescription thereof may be omitted as appropriate. The size orpositional relationship of members in the drawings may be exaggeratedfor the sake of clarity.

First Embodiment

FIG. 1 is a schematic perspective view of the light emitting device 1according to the first embodiment. FIG. 2 is a top view of the lightemitting device 1 corresponding to FIG. 1. FIG. 3 is a cross-sectionalview of the light emitting device 1 taken along line III-III in FIG. 2.FIG. 4 is a schematic perspective view of the light emitting device 1 inwhich illustration of a light-shielding member 100 is omitted fordescribing the internal configuration of the light emitting device 1.FIG. 5 is a schematic top view corresponding to FIG. 4. FIG. 6 is aschematic perspective view of the light emitting device 1 in whichillustration of a light-shielding member 100, the light-transmissivemember, and a wavelength conversion member are omitted for describingthe internal configuration. FIG. 7 is a schematic top view correspondingto FIG. 6. FIG. 8 is a schematic top view of an upward-facing surface 12(a disposition surface) of a base member 10 in an enlarged manner withreference to FIG. 7. FIG. 8 does not show some elements so as to clarifythe positional relationship between semiconductor laser elements 20 andlight-reflective members 40. FIG. 9 is a schematic perspective view of alight-transmissive member 80 and a wavelength conversion member 90 beingbonded to each other. FIG. 10 is a schematic top view corresponding toFIG. 9. FIG. 11 is a schematic top view in which the wavelengthconversion member 90 is shown in a transparent manner for describing thebonding surface between the light-transmissive member 80 and thewavelength conversion member 90. FIG. 12 is a schematic bottom view ofthe wavelength conversion member 90 according to the first embodiment.

The light emitting device 1 includes a base member 10, two semiconductorlaser elements 20, two submounts 30, two light-reflective members 40, aprotective element 50, a temperature measuring element 60, wirings 70, alight-transmissive member 80, a wavelength conversion member 90, and alight-shielding member 100.

The base member 10 has a recessed shape recessed from an upper surfaceof the base member 10 toward a lower surface of the base member 10. In atop view, the base member 10 has a rectangular outer shape, and therecess is formed inward of a periphery of the base member 10 forming theouter shape of the base member 10. The base member 10 includes an uppersurface 11, an upward-facing surface 12, a lower surface 13, innerlateral surfaces 14, and outer lateral surfaces 15. The inner lateralsurfaces 14 and the upward-facing surface 12 form the recess. In a topview, the rectangular outer shape is formed by the outer lateralsurfaces 15 which intersect with the upper surface 11. In a top view, arectangular frame is defined by the inner lateral surfaces 14, whichintersect with the upper surface 11. The frame surrounds the recess.

The four sides forming the quadrangular outer shape in a top view (theouter lateral surface 15) are parallel to respective closest ones of thefour sides forming the rectangular frame in a top view (the innerlateral surfaces 14 in a top view). In the present specification, adistance between each of sides corresponding to the outer shape and acorresponding one of sides corresponding to the frame may refer to adistance between their respective midpoints. That is, in a combinationof a single side of the outer shape and a single side of the frame withthe smallest distance between their respective midpoints, the singleside of the outer shape and the midpoint of the single side of the frameare in parallel. As used herein, the expression “parallel” encompasses adeviation of 5 degrees or less from strictly parallel configuration.

The base member 10 includes at least two stepwise portions 16 locatedinward of the frame. Each of the stepwise portions 16 includes an uppersurface and a lateral surface which intersects with the upper surfaceand extends downward. Accordingly, the inner lateral surfaces 14 of thebase member 10 include lateral surfaces intersecting with the uppersurface 11 of the base member 10 and the lateral surfaces of thestepwise portions.

As used herein, the two stepwise portions 16 are referred to as a firststepwise portion 161 and second stepwise portion 162 in sequence from anupward-facing surface 12 side. The base member 10 may include anyappropriate number, other than two, of stepwise portions 16. Forexample, the base member 10 may include a single stepwise portion 16.

Intersection between two surfaces can be understood from the drawings.For example, the outer lateral surfaces 15 may be regarded asintersecting with the upper surface 11 and the lower surface 13. Also,for example, the upper surface of the first stepwise portion 161 can beregarded as intersecting with the lateral surfaces of the secondstepwise portions 162, which are lateral surfaces of the base member 10extending upward from the upper surface of the first stepwise portion161, at corresponding edges of the first stepwise portion 161, andintersecting with lateral surfaces of base member 10 intersecting withthe upper surface 11 at other corresponding edges of the first stepwiseportion 161. This is similar for intersection between sides of the basemember 10.

A ceramic may be used for a main material of the base member 10.Examples of the ceramic include aluminum nitride, silicon nitride,aluminum oxide, and silicon carbide. Any appropriate insulating materialother than ceramic, may be employed as the main material of the basemember 10.

The base member 10 is provided with a plurality of metal films 17. Theupper surface 11 of the base member 10 is provided with six metal films171, the upward-facing surface 12 is provided with five metal films 172,and the upper surfaces of the second stepwise portions 162 are providedwith two metal films 173. The four metal films 172 on the upward-facingsurface 12 and the two metal films 173 on the upper surfaces of thesecond stepwise portions 162 are connected to respective ones of the sixmetal -films 171 on the upper surface 11 via metal members passinginside the base member 10. The upper surface of the first stepwiseportion 161 is also provided with a metal film.

In one example, on the upper surface 11, three metal films 171 areprovided to a region corresponding to a side of the upper surface 11 ina top view. As used herein, the expression “a region corresponding to aside of the upper surface 11” refers to a region between a side of theouter shape of the base member 10 and a closest one of the sides of theframe, as described above. Further, a region between the two sidesrefers to a region in which any straight line connecting any point onone of the two sides and any point on the other of the two side can belocated. The upper surface 11 includes regions corresponding to twoopposite sides of the upper surface 11, each of which is a regionbetween a corresponding one of two opposite sides of the outer shape ofthe base member 10 and a closest one of the sides of the frame. Thethree metal films 171 are provided for each of the regions correspondingto two opposite sides of the upper surface 11. These three metal films171 are arranged adjacent to one another.

As used herein, a region corresponding to one of two sides of the uppersurface 11 at each of which the three metal films 171 are disposed isreferred to as a “first region 111”, one of two regions corresponding totwo sides intersecting with the first region 111 is referred to as a“second region 112”, and a region corresponding to the other of the twosides of the upper surface 11 at each of which the three metal films 171are disposed is referred to as a “third region 113”, and one of tworegions corresponding to two sides intersecting with the third region113 and being other than the second region 112 is referred to as a“fourth region 114”. In FIG. 2, the first to fourth regions 111 to 114are hatched.

One of the three metal films 171 disposed on the first region 111includes a portion extending from the first region 111 to the secondregion 112. One of the three metal films 171 disposed on the thirdregion 113 includes a portion extending from the third region 113 to thefourth region 114.

The portion of the metal film 171 extending to the second region 112forms an alignment mark 18 in the second region 112. The portion of themetal film 171 extending to the fourth region 114 forms an alignmentmark 18 in the fourth region 114. As used herein, the alignment mark 18in the second region 112 is referred to as a “first alignment mark 181”,and the alignment mark 18 in the fourth region 114 is referred to as a“second alignment mark 182”.

Alternatively, an alignment mark 18 connected to none of the three metalfilms 171 arranged adjacent to one another may be employed. That is, analignment mark separated from the three metal films 171 may be employed.The alignment marks may be formed using any appropriate method otherthan providing the metal films.

In a top view, the first alignment mark 181 is located between astraight line that includes the side corresponding to the frame (theinner lateral surface 14) in the first region 111, and a straight lineparallel to the straight line that includes the side corresponding tothe frame in the first region 111 and passing through a midpoint of theside corresponding to the frame (the inner lateral surface 14) in thesecond region 112. In a top view, the second alignment mark 182 islocated between a straight line that includes the side corresponding tothe frame (the inner lateral surface 14) in the third region 113, and astraight line parallel to the straight line that includes the sidecorresponding to the frame in the in the third region 113 and passingthrough a midpoint of the side corresponding to the frame (the innerlateral surface 14) in the fourth region 114.

In a top view, a straight line connecting the first alignment mark 181and the second alignment mark 182 is not perpendicular or parallel toany of the four sides of the outer shape of the base member 10. Thestraight line connecting the first alignment mark 181 and the secondalignment mark 182 is not perpendicular or parallel to any of the foursides of the frame. The straight line connecting the first alignmentmark 181 and the second alignment mark 182 is inclined at an angle of 10degrees or more relative to each of the four sides of the frame. Thatis, the straight line connecting the first alignment mark 181 and thesecond alignment mark 182 is oblique relative to each of the four sidesof the outer shape or the frame of the base member 10.

As seen in FIG. 7, two alignment marks 18 are located on theupward-facing surface 12 of the base member 10. Each of the two metalfilms 172 is provided with a respective one of the two alignment marks18 located on the upward-facing surface 12 of the base member 10. Thetwo alignment marks 18 on the upward-facing surface 12 of the basemember 10 are referred to as a “third alignment mark 183” and a “fourthalignment mark 184”.

In a top view, a line connecting the third alignment mark 183 and thefourth alignment mark 184 is not perpendicular or parallel to any of thefour sides of the outer shape of the base member 10. The line connectingthe third alignment mark 183 and the fourth alignment mark 184 is notperpendicular or parallel to any of the four sides of the frame. Theline connecting the third alignment mark 183 and the fourth alignmentmark 184 is inclined at an angle of 10 degrees or more relative to anyof the four sides of the frame. The line connecting the third alignmentmark 183 and the fourth alignment mark 184 overlaps with the lineconnecting the first alignment mark 181 and the second alignment mark182. As used herein, the expression “overlapping” encompasses adeviation of 4 degrees or less about the intersection.

Any other appropriate numbers of the metal films 17 may be employed, andthe metal films 17 may be located on any other appropriate regions. Thenumber of the metal films provided to the upper surface 11 or theupward-facing surface 12 may be different from that in the descriptionabove. For example, at the upper surface 11, each of the regionscorresponding to two opposite sides of the upper surface 11 may beprovided with two metal films or a single metal film. In the lightemitting device 1, a plurality of metal films are disposed on theupward-facing surface 12 of the base member 10, the upper surface of thesecond stepwise portion 162, and the upper surface 11 of the base member10.

Each semiconductor laser element 20 has a rectangular outer shape in atop view. A lateral surface of each semiconductor laser element 20intersecting with one of two short sides of the rectangle functions asan emission end surface 21 from which light emitted from thesemiconductor laser element 20 is emitted. The upper surface and thelower surface of the semiconductor laser element 20 are has an areagreater than an area of the emission end surface 21.

Light (laser light) emitted from each semiconductor laser elementspreads to form an oval far-field pattern (hereinafter referred to as“the FFP”) in a plane parallel to the light emission end surface. TheFFP is a shape and intensity distribution of emitted light at a positionspaced apart from the emission end surface.

The FFP of light emitted from each semiconductor laser element 20 has anoval shape, which is shorter in a layer direction along each of aplurality of semiconductor layers including an active layer than in alayered direction, in which the plurality of semiconductor layers arelayered, perpendicular to the layer direction. The layer direction maybe referred to as an “FFP parallel direction”, and the layered directionmay be referred to as an “FFP perpendicular direction”.

In the present specification, according to the light intensitydistribution of the FFP of each semiconductor laser element 20, aportion of emitted light having an intensity is 1/e² or more withrespect to the peak light intensity is referred to as a “main portion ofemitted light”. The angle corresponding to the full width at halfmaximum in the light intensity distribution is referred to as a“divergence”. The divergence in the FFP perpendicular direction isreferred to as a “perpendicular-direction divergence”, and thedivergence in the FFP horizontal direction is referred to as a“horizontal-direction divergence”.

For the semiconductor laser elements 20, for example, semiconductorlaser elements configured to emit blue light can be employed. As usedherein, the “blue light” refers to light having peak emission wavelengthin a range of 420 nm to 494 nm. Examples of the semiconductor laserelements configured to emit blue light include semiconductor laserelements containing a nitride semiconductor. Examples of the nitridesemiconductor include GaN, InGaN, and AlGaN.

Each submount 30 has a rectangular prism-shape, and includes a lowersurface, an upper surface, and lateral surfaces. Of lengths of eachsubmount 30, a length of each submount 30 in the upper-lower directionis the smallest. Each submount 30 may have any appropriate shape otherthan a rectangular prism. The submounts 30 are formed of, for example,silicon nitride, aluminum nitride, or silicon carbide. Any othermaterial may be employed for the submounts 30. A metal film is disposedon the upper surface of each submount 30.

As shown in FIG. 6, each light-reflective member 40 includes twolight-reflective surfaces 41 configured to reflect light. Eachlight-reflective surface includes a plane having a light reflectance of99% or more for the peak wavelength of light irradiated to the plane.The light reflectance may be 100% or less or less than 100%.

The two light-reflective surfaces 41 have a flat shape, and are inclinedrelative to the lower surface of the light-reflective member 40 atdifferent inclination angles. That is, the two light-reflective surfaces41 are not perpendicular or parallel relative to the lower surface ofthe light-reflective member 40. The two light-reflective surfaces 41 arecontinuous to each other, to form a single integrated reflective region.

In the present specification, of the two light-reflective surfaces 41,the light-reflective surface closer to the lower surface of thelight-reflective member 40 is referred to as a “first reflective surface411”, and the light-reflective surface farther from the lower surface ofthe light-reflective member 40 is referred to as a “second reflectivesurface 412”. In each light-reflective member 40, the second reflectivesurface 412 has an inclination angle greater than an inclination angleof the first reflective surface 411 relative to the lower surface of thelight-reflective member 40. For example, the difference in inclinationangle between the first reflective surface 411 and the second reflectivesurface 412 is in a range of 10 degrees to 60 degrees.

Alternatively, each light-reflective member 40 may include three or morelight-reflective surfaces 41 which form a single integrated reflectiveregion may be provided. Alternatively, a single light-reflective surface41 may form a single reflective region. Each light-reflective member 40may include light-reflective surfaces that are not continuous. The shapeof the light-reflective surface 41 may be curved instead of being flat.

For a main material of the light-reflective members 40 which forms theouter shape of the light-reflective members 40, a glass, a metal, etc.,can be employed. The main material of the light-reflective members 40 ispreferably heat resistant, and for example, quartz or glass such as BK7(borosilicate glass), a metal such as aluminum, or Si can be used. Forthe light-reflective surfaces, for example, a metal such as Ag or Al, ora dielectric multilayer film such as Ta₂O₅/SiO₂, TiO₂/SiO₂, orNb₂O₅/SiO₂.

The protective element 50 is for preventing breakdown of specificelements (for example, the semiconductor laser elements). Examples ofthe protective element 50 include a Zener diode for which Si is used.

A temperature measuring element 60 is used as a temperature sensor formeasuring a surrounding temperature. Examples of the temperaturemeasuring element 60 include a thermistor.

The wirings 70 are used to establish electrical connection of someelements (for example, the semiconductor laser elements). Examples ofthe wirings 70 include metal wires.

The light-transmissive member 80 has a flat rectangular prism-shape, andincludes a lower surface, an upper surface, and lateral surfaces. Thelight-transmissive member is light transmissive, that is, transmitslight. As used herein, the expression “light transmissive” refers tohaving a light transmittance of 80% or more. The light-transmissivemember 80 may have any appropriate shape other than a rectangularprism-shape.

For a main material of the light-transmissive member 80, sapphire can beused. Sapphire has a relatively high refractive index and also has agreat strength. Examples of the main material other than sapphireinclude, quartz, silicon carbide, and glass.

Two metal films are disposed on an upper surface of thelight-transmissive member 80. A metal film is disposed on a lowersurface of the light-transmissive member 80. A peripheral region of eachof the upper surface and the lower surface of the light-transmissivemember 80 is provided with respective one or more metal films.Accordingly, the light-transmissive member 80 includes alight-transmissive region and a non-transmissive region in a top view ora bottom view. Further, the light-transmissive member 80 includes alight-transmissive region is provided at a center portion of thelight-transmissive member 80.

The wavelength conversion member 90 has a flat rectangular prism-shape,and includes a lower surface, an upper surface, and lateral surfaces.The wavelength conversion member 90 includes a light-transmissivewavelength conversion part 91, and a surrounding part 92. The wavelengthconversion part 91 and the surrounding part 92 are integrally formed.The inner lateral surfaces of the surrounding part 92 are in contactwith the lateral surfaces of the wavelength conversion part 91. Theouter lateral surfaces of the surrounding part 92 correspond to thelateral surfaces of the wavelength conversion member 90.

The wavelength conversion part 91 has a rectangular prism-shape. Thewavelength conversion part 91 is configured to convert light incident onthe wavelength conversion part 91 into light of a different wavelength.For a main material of the wavelength conversion member 90, an inorganicmaterial that is less prone to be decomposed by irradiation with lightcan be used. The main material of the wavelength conversion member 90may not be an inorganic material.

The wavelength conversion pail 91 may contain ceramic as the mainmaterial of the wavelength conversion part 91, and a fluorescentmaterial. Other appropriate configuration may be employed for thewavelength conversion part 91. For example, the main material of thewavelength conversion part 91 may be glass, or a nanocrystal of afluorescent material. In consideration of heat generated in thewavelength conversion part 91, a material having a inciting point in arange of 1300° C. to 2500° C. is preferably used for a main material ofthe wavelength conversion part 91.

For example, when a ceramic is employed as a main material of thewavelength conversion part 91, the ceramic may be obtained by sinteringa fluorescent material and a light-transmissive material such asaluminum oxide. The content of the fluorescent material may be in arange of 0.05 volume percent to 50 volume percent with respect to thetotal volume of ceramic. Alternatively, the ceramic may be obtained bysintering powder of a fluorescent material, that is, ceramic formed ofsubstantially just the fluorescent material.

Examples of the fluorescent material include a cerium-activatedyttrium-aluminum-garnet-based fluorescent material (YAG), acerium-activated lutetium-aluminum-garnet-based fluorescent material(LAG), a europium and/or chromium-activated nitrogen-containing calciumaluminosilicate-based fluorescent material (CaO—Al₂O₃—SiO₂), aeuropium-activated silicate-based fluorescent material ((Sr,Ba)₂SiO₄),an α-sialon fluorescent material, a β-sialon fluorescent material, andthe like. Among these, a YAG fluorescent material, having good heatresistance, is preferably used.

The surrounding part 92 has a flat rectangle prism-shape defining athrough hole at a center of the flat rectangle prism-shape. Thewavelength conversion part 91 is disposed in the through hole. The shapeof the through hole corresponds to the shape of the wavelengthconversion part 91. The surrounding part 92 surrounds the lateralsurfaces of the wavelength conversion part 91.

A ceramic may be used for a main material of the surrounding part 92.Materials other than a ceramic, such as a metal or a complex of ceramicand metal, may be employed for the surrounding part 92. For thesurrounding part 92, a material with a highly thermal conductivityconfigured to dissipate heat generated in the wavelength conversion part91 is preferably used. When a material with a highly thermalconductivity is employed for a main material of the surrounding part 92,the surrounding part 92 has a heat dissipating function of dissipatingheat in the wavelength conversion part 91. In view of this, thesurrounding part 92 may be regarded as a heat dissipating member.

For the surrounding part 92, a material having a high reflectance forlight emitted from the semiconductor laser elements 20 and a highreflectance for fluorescent emitted by the fluorescent material. When amaterial with a highly thermal conductivity is employed for a mainmaterial of the surrounding part 92, the surrounding part 92 reflectslight irradiated to the surrounding part 92 at a high reflectance. Inthis context, the surrounding part 92 can be regarded as alight-reflective member. Examples of a material with high reflectanceand high thermal conductivity include alumina (Al₂O₃) ceramic.

A conductive film is disposed on a lower surface of the surrounding part92. The conductive film has a linear shape, and overlaps with thewavelength conversion part 91 in a bottom view. Two opposite ends of thelinear conductive film are connected to the metal films disposed on thelower surface of the surrounding part 92. The two opposite ends of thelinear conductive film are connected to respective metal films differentfrom each other. The opposite ends of the linear conductive film may belocated in the vicinity of the wavelength conversion part 91 instead ofoverlapping with the wavelength conversion part 91.

The conductive film preferably has a narrow linear shape. The expression“narrow linear shape” as used herein refers to, for example, a length ofa portion of the conductive film having a width smaller than a width ofthe wavelength conversion part 91 in a bottom view is longer than theouter periphery of the wavelength conversion part 91. As used herein,the expression “width of the wavelength conversion part 91,” refers to,for example, when the outer shape of the wavelength conversion part 91is a quadrangular shape, the width of the short side of the wavelengthconversion part 91. When the outer shape of the wavelength conversionpart 91 is an oval shape, the expression “width of the wavelengthconversion part 91” as used herein refers to the width of the minor axisof the wavelength conversion part 91. When the outer shape of thewavelength conversion part 91 is a shape other than these shapes, thewidth of the shape is appropriately determined according to theseexamples.

The wavelength conversion member 90 may be obtained by, for example,integrally molding the wavelength conversion part 91, which is made of amolded body such as a sintered body, and a powder material that is toform the surrounding part 92 and sintering the wavelength conversionpart 91 and the powder material that are integrally molded.Alternatively, the wavelength conversion member 90 may be obtained by,for example, integrally molding the surrounding part 92, which is amolded body such as a sintered body, and a powder material that is toform the wavelength conversion part 91, and sintering the surroundingpart 92 and the powder material that are integrally molded. For thesintering, for example, spark plasma sintering (SPS) or hot pressing(HP) can be employed.

For the conductive film, indium tin oxide (ITO) can be used. ITO has ahigh transmittance for visible light. The conductive film formed of ITOis light transmissive, and accordingly can be regarded as alight-transmissive conductive film.

The light-shielding member 100 defines a through hole at a centerportion of the light-shielding member 100. At a lower surface side ofthe light-shielding member 100, the light-shielding member 100 has aprojection surrounding the through hole. In other words, thelight-shielding member 100 has a recessed shape recessed at the centerportion at the lower surface side.

The light-shielding member 100 is made of a light-shielding resin. Asused herein, the expression “light-shielding” refers to the property ofnot transmitting light. The light-shielding property may be achieved by,in addition to the light shielding characteristic, the light-absorbingcharacteristic or the light-reflective characteristic. For example, thelight-shielding property may be achieved by resin containing filler of alight diffusing member and/or a light absorbing member.

Examples of the resin forming the light-shielding member 100 includeepoxy resin, silicone resin, acrylate resin, urethane resin, phenolicresin, and BT resin. Examples of the light-absorbing filler include adark-color pigment such as carbon black.

Next, a description will be given of the procedure of manufacturing thelight emitting device 1 with the elements described above. Twolight-reflective members 40 are disposed on the upward-facing surface 12of the base member 10. Accordingly, the upward-facing surface 12 of thebase member 10 can be regarded as the disposition surface on which thelight-reflective members 40 are disposed. Each of the twolight-reflective members 40 is disposed on a respective one of differentmetal films 172, and respective lower surfaces the light-reflectivemembers 40 are bonded to the upward-facing surface 12 of the base member10. Disposing position of the light-reflective members 40 is determinedaccording to the alignment marks 18 and reference lines SL for thelight-reflective members 40.

The “reference lines SL for the light-reflective members 40” as usedherein refer to lines serving as the aligning reference when disposingthe light-reflective members 40. The reference line SL may be located ata predetermined region of the corresponding light-reflective member 40,or may be determined according to configuration of the predeterminedregion of the corresponding light-reflective member 40. That is, thereference lines SL can be obtained according to the predeterminedregions of respective light-reflective members 40.

In the light emitting device 1, in a top view, a straight line passingthrough a side corresponding the upper edge of the light-reflectivesurface 41 serves as the reference line SL for the light-reflectivemember 40. Other lines may be employed for the reference line. Forexample, a line passing through a side corresponding to the lower edgeof the light-reflective surface 41 may serve as the reference line.Alternatively, for example, when the upper surface of thelight-reflective member 40 has a rectangular shape, with two apexes ofthe rectangular upper surface of the light-reflective member 40 servingas characteristic points, a line passing through the two characteristicpoints may serve as the reference line.

Each light-reflective member 40 is disposed such that the reference lineSL is parallel to a line rotated at a predetermined angle with respectto a line passing through the first alignment mark 181 and the secondalignment mark 182 in a top view (i.e., the reference line SL isparallel to a line that is oblique to a light passing through the firstalignment mark 181 and the second alignment mark 182 at a predeterminedangle). As used herein, the line passing through a pair of alignmentmarks is referred to as a “first line 1L”, and the line rotated at apredetermined angle relative to the first line 1L is referred to as a“second line 2L”. The pair of alignment marks is the first alignmentmark 181 and the second alignment mark 182.

The two light-reflective members 40 are point-symmetrically disposed.The two light-reflective members 40 are symmetrically disposed relativeto the midpoint CP of the line between (connecting) the first alignmentmark 181 and the second alignment mark 182.

More specifically, using a mounter, the midpoint CP is determinedaccording to the first alignment mark 181 and the second alignment mark182, and the second line 2L is determined to be rotated relative to thefirst line 1L at a predetermined angle about the midpoint CP. In a topview, according to an XY plane with the second line 2L in an Xdirection, a direction perpendicular to the second line 2L in a Ydirection, and the midpoint CP at coordinates of (0, 0), the twolight-reflective members 40 are disposed such that the reference linesSL are parallel to the second line 2L and the two light-reflectivemembers 40 are point-symmetrical about the coordinates (0, 0).

In a top view, the second line 2L is parallel to the side correspondingto the frame (the inner lateral surface 14) in the first region 111 orthe third region 113. The second line 2L is perpendicular to the sidecorresponding to the frame (the inner lateral surface 14) in the secondregion 112 or the fourth region 114. As used herein, “parallel” and“perpendicular” encompass configurations with a deviation of 6 degreesor less from strictly parallel configuration and strictly perpendicularconfiguration.

That is, the predetermined angle with respect to the first line 1L isdetermined. according to an angle defined by the first line 1L and aline passing through a side corresponding to the frame of the basemember 10 as designed. The predetermined angle may be set such that thesecond line 2L is oblique with respect to a side of the frame of thebase member 10 instead of being parallel or perpendicular.

The first line 1L may be the line passing through the third alignmentmark 183 and the fourth alignment mark 184. Alternatively, the firstline 1L may be a line passing through any two alignment marks 18, orthree or more alignment marks 18. Accordingly, the first line 1L may beregarded as a line determined according to a plurality of alignmentmarks 18.

The two light-reflective members 40 may be disposed to be symmetricalrelative to the midpoint CP of the line connecting the third alignmentmark 183 and the fourth alignment mark 184.

In a top view, the two light-reflective members 40 do not overlap withthe third alignment mark 183 and the fourth alignment mark 184.Accordingly, at this time, the third alignment mark 183 and the fourthalignment mark 184 can be visually recognized from an upper surfaceside.

Next, the protective element 50 and the temperature measuring element 60are disposed on the upward-facing surface 12 of the base member 10. Theprotective element 50 is disposed and bonded onto a metal film 172 onwhich one of the two light-reflective members 40 is disposed. Thetemperature measuring element 60 is disposed and bonded onto anothermetal film 172 which is different from the metal films 172 on each ofwhich a respective one of the two light-reflective members 40 isdisposed.

Next, the two submounts 30 are disposed on the upward-facing surface 12of the base member 10. In a top view, the submounts 30 are disposed suchthat corresponding one or more sides of the upper surface are parallelto the first line. Each of the two submounts 30 is disposed on arespective one of different metal films 172, and respective lowersurfaces of the submounts 30 are bonded to the upward-facing surface 12of the base member 10. Each of the two submounts 30 is disposed on arespective one of the metal films 172 on each of which thelight-reflective members 40 is disposed.

Each submount 30 and a corresponding light-reflective member 40 may bedisposed on different metal films 172. In a top view, the two submounts30 do not overlap with the third alignment mark 183 and the fourthalignment mark 184. Accordingly, at this time, the third alignment mark183 and the fourth alignment mark 184 can be visually recognized fromthe upper surface side.

Next, the semiconductor laser elements 20 are disposed on the submounts30. Each of the two semiconductor laser elements 20 is disposed on theupper surface of a respective one of different submounts 30, and thelower surface of each of the two semiconductor laser elements 20 isbonded to the upper surface of a respective one of the submounts 30. Thedisposing positions of the semiconductor laser elements 20 aredetermined according to the alignment marks 18 and the light emissionend surfaces 21 of the semiconductor laser elements 20.

Each semiconductor laser element 20 is disposed such that the emissionend surface 21 is parallel to the first line 1L in a top view. The twosemiconductor laser elements 20 are point-symmetrically disposed. Thetwo semiconductor laser elements 20 are disposed to be symmetricalrelative to the midpoint CP of the line connecting the first alignmentmark 181 and the second alignment mark 182.

More specifically, using the mounter, the first line 1L is determinedaccording to the first alignment mark 181 and the second alignment mark182, and the midpoint CP is determined. In a top view, according to anXY plane with the first line 1L in an X direction, a directionperpendicular to the first line 1L in a Y direction, and the midpoint CPat coordinates of (0, 0), the two semiconductor laser elements 20 aredisposed such that emission end surfaces are parallel to the first line1L and the two semiconductor laser elements 20 are point-symmetricalabout the coordinates (0, 0).

Thus, the two semiconductor laser elements 20 and the twolight-reflective members 40 are disposed to be symmetrical about thesame point. The two semiconductor laser elements 20 may be disposed tobe symmetrical relative to the midpoint CP of the line connecting thethird alignment mark 183 and the fourth alignment mark 184.

In a top view, the two semiconductor laser elements 20 do not overlapwith the third alignment mark 183 and the fourth alignment mark 184.Accordingly, at this time, the third alignment mark 183 and the fourthalignment mark 184 can be visually recognized from the upper surfaceside.

The emission end surface 21 of each of the two semiconductor laserelements 20 is not parallel or perpendicular to a corresponding one ofthe inner lateral surfaces 14 or a corresponding one of the outerlateral surfaces 15 of the base member 10 in a top view. Accordingly,each of the emission end surfaces 21 is not parallel or perpendicular tothe upper edge of a corresponding one of the light-reflective surfaces41. That is, the semiconductor laser elements 20 are disposed such thattheir respective emission end surfaces 21 are oblique relative torespective ones of the inner lateral surfaces 14 and respective ones ofthe outer lateral surfaces 15 of the base member 10 or to the upperedges of the light-reflective surfaces 41 in a top view.

In the light emitting device 1, for each of the semiconductor laserelements 20, the oblique angle defined by a line including the emissionend surface 21 of each semiconductor laser element 20 and a lineincluding the upper end of corresponding light-reflective surface 41 isin a range of 25 degrees to 35 degrees in a top view. The oblique angledefined by the line including the emission end surface 21 and the lineincluding the upper end of a corresponding light-reflective surface 41is indicated by the angle α in FIG. 8, and not the angle β. The obliqueangle defined by the line including the emission end surface 21 and theline including the upper end of a corresponding light-reflective surface41 may be in a range of 10 degrees to 80 degrees. In consideration ofirradiation of light on the light-reflective members 40, the obliqueangle is preferably designed to be 45 or less.

The light emitted from the emission end surface 21 of each of the twosemiconductor laser elements 20 is irradiated to a correspondinglight-reflective member 40. The expression “correspondinglight-reflective member 40” refers to the light-reflective member 40disposed on the same metal film. Each semiconductor laser element 20 isdisposed so that at least the main portion light is irradiated on thecorresponding light-reflective surface 41.

Mounting using the first line 1L determined directly from the alignmentmarks 18 can be performed more precisely than mounting using the secondline 2L rotated with respect to the first line 1L about the midpoint CP.Accordingly, when mounting each semiconductor laser element 20 and acorresponding light-reflective member 40 to be obliquely arranged in atop view, performing the mounting such that the emission end surface 21is aligned with the first line and the light-reflective member 40 isaligned with the second line allows for precisely setting thepropagation direction of light reflected by the light-reflective member40.

Mounting the light-reflective member 40 to be aligned with the secondline rotated with respect to the first line at a predetermined angle ina top view allows for more precisely setting the oblique angle definedby the semiconductor laser element 20 and the light-reflective member40, than mounting the light-reflective member 40 to be aligned with apredetermined side of the inner lateral surfaces 14 or a predeterminedside of the outer lateral surfaces 15 of the base member 10.

In the corresponding pair of each semiconductor laser element 20 and acorresponding light-reflective member 40, the semiconductor laserelement 20 is positioned farther from the midpoint CP of the lineconnecting the first alignment mark 181 and the second alignment mark182 than the light-reflective member 40. Accordingly, light emitted fromthe semiconductor laser element 20 propagates in the directionapproaching the midpoint CP. At least one of the two semiconductor laserelements 20 is disposed in the vicinity of the temperature measuringelement 60. Due to symmetrical arrangement of the two semiconductorlaser elements 20, it is considered that there may not exist a largedifference in temperature between the two semiconductor laser elements20.

The submounts 30 on which the semiconductor laser elements 20 aredisposed function as heat dissipating members for dissipating heatgenerated in the semiconductor laser elements 20 in the light emittingdevice 1. In order for the submounts 30 to function as heat dissipatingmembers, a material with a thermal conductivity greater than thesemiconductor laser elements 20 are used for the submounts 30. When amaterial with a thermal conductivity greater than the upward-facingsurface 12 of the base member 10 are used for the submounts 30, greaterheat dissipation effect can be exhibited.

The submounts 30 can be used to adjust the emission position of lightfrom the semiconductor laser elements in the light emitting device 1.For example, when irradiating light such that light propagating alongthe optical axis is parallel to the upward-facing surface 12 and isirradiated to a predetermined position of each light-reflective surface41, the submounts can be used as adjustment members.

Next, a plurality of wirings 70 are bonded for establishing electricconnection with the semiconductor laser elements 20, electric connectionwith the protective element 50, and electric connection with thetemperature measuring element 60. For electrical connection, the metalfilms 172 provided on the upward-facing surface 12 of the base member 10are used. Accordingly, the metal films 172 disposed on the upward-facingsurface 12 of the base member 10 function as conduction regions forelectric connection.

The wirings 70 are bonded so that the two semiconductor laser elementsand the protective element 50 are connected in series. Further, thewirings 70 are bonded so that the temperature measuring element 60 iselectrically connected separately from the two semiconductor laserelements and the protective element 50.

Some of the wirings 70 include respective first end portions bonded tothe upper surface of a corresponding one of the semiconductor laserelements 20, and respective second end portions bonded to acorresponding one of the metal films 172 disposed on the upward-facingsurface 12 of the base member 10. Accordingly, the disposing positionfor bonding the first end portions of corresponding wirings 70 to theupper surfaces of the semiconductor laser elements 20 is determinedaccording to the first line. This allows the corresponding wirings 70 tobe precisely bonded to the upper surface of the semiconductor laserelements 20 having narrow width.

Next, the light-transmissive member 80 is disposed on the upper surfaceof the base member 10. The light-transmissive member 80 is disposed onthe upper surface of the stepwise portion 16 of the base member 10, witha lower surface of the light-transmissive member 80 facing an uppersurface of the stepwise portion 16. More specifically, thelight-transmissive member 80 is bonded to the upper surface of the firststepwise portion 161. The metal films disposed along the peripheralregion of the lower surface of the light-transmissive member 80 and themetal film disposed on the upper surface of the first stepwise portion161 are bonded to be secured to each other via Au—Sn or the like.

Bonding the light-transmissive member 80 to the base member 10 forms aclosed space where the semiconductor laser elements 20 are disposed. Inthis manner, in the light emitting device 1, the light-transmissivemember 80 can function as a cover. This closed space is hermeticallysealed. The hermetic sealing avoids collection of organic substances orthe like at the emission end surfaces of the semiconductor laserelements 20.

In a top view, the light-transmissive member 80 overlaps with the thirdalignment mark 183 and the fourth alignment mark 184. On the other hand,the light-transmissive member 80 does not overlap with the firstalignment mark 181 and the second alignment mark 182. Accordingly, thefirst alignment mark 181 and the second alignment mark 182 are locatedoutward of the bonding region of the base member 10 where the basemember 10 is bonded to the light-transmissive member 80.

The light-transmissive member 80 is bonded to the base member 10 withthe wavelength conversion member 90 bonded to its upper surface. Thatis, the light-transmissive member 80 is disposed on the upper surface ofthe base member 10, and the wavelength conversion member 90 is disposedon the upper surface of the light-transmissive member 80. Accordingly,the wavelength conversion member 90 is disposed above the semiconductorlaser elements 20 and the light-reflective members 40 disposed on theupward-facing surface 12.

Light emitted from the two semiconductor laser elements 20, particularlya main portion of light emitted from each of the two semiconductor laserelements 20, is reflected by respective corresponding light-reflectivesurfaces 41 of respective corresponding light-reflective members 40, isthen transmitted through the light-transmissive member 80, and isincident on the lower surface of the wavelength conversion part 91.

A portion of or the entirety of light incident on the wavelengthconversion part 91 is converted into light of a different wavelength bythe wavelength conversion part 91. The laser light or thewavelength-converted light is emitted from the upper surface of thewavelength conversion part 91 to the outside of the light emittingdevice 1. That is, the upper surface of the wavelength conversion part91 serves as the light extraction surface of the light emitting device1.

In a top view, the midpoint CP of the line connecting the firstalignment mark and the second alignment mark is located in the regionwhere the wavelength conversion part is provided (i.e., the midpoint CPoverlaps the wavelength conversion part 91 in a top view). Sucharrangement allows light emitted from the two semiconductor laserelements 20 to be effectively incident on the wavelength conversion part91.

Concentration of heat generated by the wavelength conversion onto aparticular portion tends to cause deterioration of the wavelengthconversion part 91. Therefore, the distribution of light incident on thewavelength conversion part 91 is preferably diffused. For example, it ispreferable that respective high-intensity portions of laser lightsemitted from respective ones of the two semiconductor laser elements 20do not overlap with each other by their high-intensity portions. Thelight emitting device 1 has a configuration such that light propagatingthrough the optical axis does not pass the center of the wavelengthconversion part.

The surrounding part 92 is bonded to the light-transmissive member 80,so that the wavelength conversion member 90 is bonded to thelight-transmissive member 80. In the surrounding part 92, the metal filmconnected to one end of the conductive film and one of the two metalfilms of the light-transmissive member 80 are bonded to each other; andthe metal film connected to other end of the conductive film and theother one of the two metal films are bonded to each other. Thus,electric connection is established with the two metal films of thelight-transmissive member 80 functioning as the electrodes.

The conductive film is a narrow linear-shaped film to extending on thelower surface of the wavelength conversion part 91. Accordingly, when anerror such as breakage occurs in the wavelength conversion part 91, theconductive film is also cracked according to the shock caused by theerror, resulting in a change in the electric connection state.Accordingly, by detecting this change (for example, a large increase inresistance), the error of the wavelength conversion part 91 can bedetected. The conductive film is regarded as an error detecting element93, which is a sensor configured to detect an error of the wavelengthconversion part 91.

The upper surface of the light-transmissive member 80 is has a sizegreater than the lower surface of the wavelength conversion member 90.In a top view, the upper surface of the light-transmissive member 80surrounds the lower surface of the wavelength conversion member 90.Alternatively, the upper surface of the light-transmissive member 80surrounds the wavelength conversion member 90. In a top view, the twometal films on the upper surface of the light-transmissive member 80 areprovided across the region overlapping with the lower surface of thewavelength conversion member 90 and the region not overlapping with thelower surface of the wavelength conversion member 90.

Next, wirings 70 for electrically connecting the error detecting element93 are bonded. For establishing the electric connection, the metal films173, disposed on the second stepwise portions 162 of the base member 10,and the region in the metal film on the light-transmissive member 80which does not overlap with the lower surface of the wavelengthconversion member 90 are used. Accordingly, these metal films functionas the conduction regions provided for establishing electricalconnection. The wirings 70 for electrically connecting the errordetecting element 93 includes respective first end portions bonded tothe metal films on the upper surface of the light-transmissive member80, and respective second end portions bonded to the metal films 173 onthe upper surfaces of the second stepwise portions 162.

As used herein, wirings 70 for electrically connecting the semiconductorlaser elements 20, the protective element 50, and the temperaturemeasuring element 60 are referred to as “first wirings 71”, and owirings 70 electrically connecting the error detecting element 93 arereferred to as “second wirings 72”.

The six metal films 171 on the upper surface 11 of the base member 10consist of two metal films for supplying electricity to thesemiconductor laser elements 20, two metal films for supplyingelectricity to the temperature measuring element 60, and two metal filmsfor supplying electricity to the error detecting element 93.Accordingly, the metal films 171 disposed on the upper surface 11 of thebase member 10 function as conduction regions for establishingelectrical connection.

Other configurations may be employed for supplying electricity. Forexample, when the light emitting device 1 does not include thetemperature measuring element 60 and the error detecting element 93, themetal films need not include metal films corresponding to thesecomponents, or, for example, the corresponding metal films may be usedfor other purposes.

The metal film 171 which forms the first alignment mark 181 includes aconduction region in the first region 111, and an alignment region forthe alignment mark 18 in the second region 112. At least the firstalignment mark 181 is not formed in the first region 111.

The metal film 171 which forms the second alignment mark includes aconduction region in the third region 113, and an alignment region forthe alignment mark 18 in the fourth region 114. At least the secondalignment mark 182 is not formed in the third region 113.

Next, the light-shielding member 100 is formed inward of the frameformed by the upper surface 11 of the base member 10. Thelight-shielding member 100 is formed to fill the space between the basemember 10 and the wavelength conversion member 90. The light-shieldingmember 100 is formed by pouring resin, and curing the poured resin byapplying heat. The resin filling the space allows for obtaininglight-shielding property greater than in the case in which thelight-shielding member 100 having been molded into a predetermined shapeis fitted into the space. The resin does not enter the closed spacewhere the semiconductor laser elements 20 are disposed.

The light-shielding member 100 is in contact with the inner lateralsurfaces 14 of the base member 10 intersecting with the upper surface11, the upper surfaces of the stepwise portions 16 of the base member10, the lateral surfaces of the light-transmissive member 80, the uppersurface of the light-transmissive member 80, and the lateral surfaces ofthe wavelength conversion member 90. The light-shielding member 100 doesnot reach the upper surface of the wavelength conversion member 90.Alternatively, the light-shielding member 100 reaches the upper surfaceof the surrounding part 92 without reaching the upper surface of thewavelength conversion part 91. With this structure, light emitted fromthe semiconductor laser elements 20 can be inhibited from being leakedfrom portions other than the wavelength conversion part 91.

The second wirings 72 is embedded in the light-shielding member 100.That is, at the time where the light-shielding member 100 is formed, thesecond wirings 72 are not exposed outside the light emitting device 1.This allows for protecting the second wirings 72 from moisture or thelike. The second wirings 72 is not necessarily embedded in thelight-shielding member 100.

The wavelength conversion member 90 penetrates through the through holeformed in the light-shielding member 100. The projecting portion of theprojecting shape formed at the lower surface side of the light-shieldingmember 100 is fitted into the groove between the lateral surface of thelight-transmissive member 80 and the inner lateral surface 14 of thebase member 10.

The light-shielding member 100 covers the metal region that has beenexposed inward of the frame formed by the upper surface 11 of the basemember 10 in a top view. In the light emitting device 1, thelight-shielding member 100 is made of an insulating material, tofunction as an insulating member. Thus, the conduction region forsupplying electricity to the light emitting device 1 from an externalpower supply can be limited to be located outside the space defined bythe recessed shape.

In a top view, the light-shielding member 100 does not overlap with thefirst alignment mark 181 and the second alignment mark 182. That is, thelight-shielding member 100 does not cover the first alignment mark 181and the second alignment mark 182.

The light emitting device 1 is manufactured through the steps describedabove. The light emitting device 1 includes the first alignment mark 181and the second alignment mark 182 at an outer periphery of the lightemitting device 1. Accordingly, when mounting the manufactured lightemitting device 1 on other member or the like, the mounting can becarried out precisely using the first alignment mark 181 and the secondalignment mark 182.

The third alignment mark 183 and the fourth alignment mark 184 may beused for mounting an element on the upward-facing surface 12 of the basemember 10 while using the first alignment mark 181 and the secondalignment mark 182 for mounting other element. Depending on theperformance of the mounter, the mounting may be further preciselycarried out using the alignment marks 18 located in a plane same as theupward-facing surface 12, which is the disposition surface.

Alternatively, the first alignment mark 181 and the second alignmentmark 182 may be used in mounting a member not included in the lightemitting device 1 while using the third alignment mark 183 and thefourth alignment mark 184 for mounting an element of the light emittingdevice 1. Any other appropriate use of the alignment marks 18 may beemployed. the alignment marks 18 on the upper surface 11 and thealignment marks 18 on the upward-facing surface 12 may be selectivelyused according to the steps.

The steps described above is merely an example, and the order of thesteps may partially be changed. For example, before disposing thelight-reflective member 40, the submounts 30 and the semiconductor laserelements 20 may be disposed. Alternatively, for example, thesemiconductor laser elements 20 may be disposed on the submounts 30, andthereafter the submounts 30 may be disposed on the upward-facing surface12. Any other appropriate changes in order of steps can be flexiblymade, unless they are apparently non-realizable. The expression“apparently non-realizable order of steps” refers to, for example,forming the closed space with the cover and thereafter disposing thesemiconductor laser elements 20 in the closed space.

Second Embodiment

FIG. 13 is a schematic perspective view of a light emitting device 2according to a second embodiment. FIG. 14 is a schematic top view of thelight emitting device 2 corresponding to FIG. 13. FIG. 15 is a schematicperspective view of the light emitting device 2 without alight-shielding member 101 for describing the internal configuration.

The light emitting device 2 according to the second embodiment isdifferent from the light emitting device 1 according to the firstembodiment in the shape of the base member and accordingly the shape ofthe light-shielding member. In the light emitting device 1, eachalignment mark is formed by disposing a metal film on a region where thealignment mark is to be positioned. On the other hand, in the lightemitting device 2, each alignment mark is formed by disposing a metalfilm surrounding a region where the alignment mark is to be positioned.

In the base member 10 of the light emitting device 1, the secondstepwise portions 162 are formed over the entire length of the sidescorresponding to the frame in the second region 112 and the fourthregion 114 in a top view. On the other hand, in the base member 210 ofthe light emitting device 2, second stepwise portions 163 are formed ata portion of the side of the frame in the second region 112 and at aportion of the side of the frame in the fourth region 114 in a top view.The first to fourth regions in the second embodiment are identical tothose described in the first embodiment and, therefore, are not denotedby the reference characters in FIGS. 13 to 15.

In a top view, the second stepwise portion 163 is not formed in otherpart of the side corresponding to the frame in the second region 112,and the second stepwise portion 163 is not formed in other part of theside corresponding to the frame in the fourth region 114. Morespecifically, in each of the sides corresponding to the frame in thesecond region 112 and the fourth region, the second stepwise portion 163is formed at a center portion, and not on portions on both sides of thecenter portion.

In the portions where the second stepwise portions 163 are not formed,the upper surface of the first stepwise portion 161 intersects withlateral surfaces which intersect with the upper surface 11. Accordingly,each of the second region 112 and the fourth region 114 of the uppersurface 11 are defines a recess at the portion intersecting with thecorresponding inner lateral surface 14 in a top view. The width of theupper surface 11 (the distance between the inner lateral surface 14 andthe outer lateral surface 15) is greater at the portions on both sidesof each of the recesses than at the recesses.

As used herein, the portions of the upper surface 11 having a smallerwidth at the recess is referred to as “narrow portions of the uppersurface 11”, and the portions of the upper surface 11 having a greaterwidth on both sides of the recess is referred to as “wide portions ofthe upper surface 11”. In a top view, in each of the second region 112and the fourth region, the second stepwise portion 163 is locatedbetween a line passing through the inner lateral surface 14 of the wideportion and the line passing through the outer lateral surface 115.

In the light emitting device 2, alignment marks 19 are located at thewide portions of the upper surface 11. Each of the alignment marks 19,namely, a first alignment mark 191 and a second alignment mark 192, isformed by disposing a metal film to surround the region serving as thealignment mark. Specific examples of a method of forming the alimentmarks 19 include disposing a metal film over a mask disposed on a regionwhere the alignment mark is to be provided, and then removing the mask.Alternatively, for example, after disposing a metal film, a portion ofthe metal film where the alignment mark is to be provided be removed.

When forming the alignment mark using the metal film 171, there may be acase in which disposing the metal film to surround the region serving asthe alignment mark, as in the light emitting device 2, is more stablyperformed than disposing the metal film to include a portion having ashape of the alignment mark, as in the light emitting device 1. On theother hand, disposing the metal film to surround the region serving asthe alignment mark requires a greater region for forming the alignmentmark than when disposing the metal film to include a portion having ashape of the alignment mark.

In the light emitting device 1, when the base member has a shape inwhich each second stepwise portion is formed over the entire length of acorresponding one of the sides corresponding to the frame, a size of theouter shape of the base member is required to be increased in order toform the alignment mark by disposing the metal film to include a portionhaying a shape of the alignment mark. When each second stepwise portionis partially formed along a corresponding one of the sides correspondingto the frame as in the light emitting device 2, the alignment mark canbe formed by disposing the metal film to surround the region serving asthe alignment mark without increasing the size of the outer shape of thebase member.

Accordingly, in a top view, a line parallel to the side corresponding tothe frame in the first region 111 or the third region 113 and passingthrough the first alignment mark 191 or the second alignment mark 192does not intersect with a corresponding one of the second stepwiseportions 163. Each of the second stepwise portions 163 is formed in theregion between the line parallel to the side corresponding to the framein the first region 111 or the third region 113 and passing through thefirst alignment mark 191 and the line parallel to the side correspondingto the frame in the first region 111 or the third region 113 and passingthrough the second alignment mark 192, and not formed outside thisregion. The line connecting the first alignment mark 191 and the secondalignment mark 192 does not intersects with the second stepwise portions163.

In the light emitting device 2, in the direction of the sidecorresponding to the frame in the second region 112, the length of thefirst stepwise portion 161 is greater than the length of the secondstepwise portion 163. The difference in length between the firststepwise portion 161 and the second stepwise portion 163 is greater thanthat in the light emitting device 1. The second wirings 72 are bonded tothe metal films on the upper surfaces of the second stepwise portions163.

The light-shielding member 101 may be disposed by, for example, pouringa resin, and heating to cure the poured resin. The resin is formed of aninsulating material, and functions as an insulating member whichprotects the second wirings 72 from unintended electric conduction dueto an external factor. In order to protect the second wirings 72 fromunintended electric conduction, the insulating member is required to beformed so that the second wirings 72 are not exposed outside. As hasbeen described above, the second stepwise portion 163 of the lightemitting device 2 has a length smaller than a length of the firststepwise portion 161 m which facilitates control of the pouring theresin.

While certain embodiments of the present invention have been describedabove, the present invention is not limited to the configuration of thelight emitting device in embodiments described in the presentspecification. For example, the present invention is applicable to alight emitting device additionally including an element which is notdescribed in the embodiments described above. Merely having a differencefrom the light emitting device described above does not form the groundsfor the inapplicability of the present invention.

That is, the present invention is also applicable to a device notincluding every element of the light emitting device in the embodimentsdescribed above. For example, when the claims do not recite some of themanufacturing steps in manufacturing of the light emitting device orsome elements of the light emitting device in the embodiments describedabove, a light emitting device or a method of manufacturing a lightemitting device including elements or manufacturing steps not describedin the claims is within the scope of the claims, while any appropriateconfigurations other than those described above may be employed andflexibility in design such as replacement, omission, change of shape,change of material, etc., may be made by a person skilled in the art.

The light emitting device according to certain embodiments of thepresent invention is applicable to a light source for a vehicleheadlight, illumination, a projector, a head-mounted display, abacklight for any other display and the like.

What is claimed is:
 1. A light emitting device comprising: one or more electrical components including a first semiconductor laser element, the first semiconductor laser element having a light emission end surface; and a base member having a first surface on which the first semiconductor laser element is disposed, the base member including a plurality of metal films including a first metal film and a second metal film, wherein the first metal film is electrically connected to at least one of the one or more electrical components, and defines a first alignment mark for aligning the first semiconductor laser element, the second metal film is electrically connected to at least one of the one or more electrical components, and defines a second alignment mark for aligning the first semiconductor laser element, and a straight line connecting the first alignment mark and the second alignment mark extends parallel to the light emission end surface of the first semiconductor laser element.
 2. The light emitting device according to claim 1, wherein the one or more electrical components further includes a second semiconductor laser element having a light emission end surface, the second semiconductor laser element is disposed on the first surface of the base member, and the straight line connecting the first alignment mark and the second alignment mark extends parallel to the light emission end surface of the second semiconductor laser element.
 3. The light emitting device according to claim 2, wherein the first semiconductor laser element and the second semiconductor laser element are disposed on the first surface of the base member so that a distance from a midpoint between the first alignment mark and the second alignment mark to the first semiconductor laser element is equal to a distance from the midpoint to the second semiconductor laser element.
 4. The light emitting device according to claim 1, further comprising a light-reflective member disposed on the base member.
 5. The light emitting device according to claim 4, further comprising a light-transmissive member through which light reflected by the light-reflective member passes, wherein the light-transmissive member overlaps the first metal film and the second metal film in a top view.
 6. The light emitting device according to claim 4, further comprising a light-transmissive member through which light reflected by the light-reflective member passes, wherein the plurality of metal films further include a third metal film defining a third alignment mark and a fourth metal film defining a fourth alignment mark, the light-transmissive member does not overlap the first metal film and the second metal film in a top view, and the light-transmissive member overlaps the third metal film and the fourth metal film in the top view.
 7. The light emitting device according to claim 1, wherein the base member has a recessed shape and has a second surface positioned higher than the first surface, and the first metal film and the second metal film are disposed on the second surface.
 8. The light emitting device according to claim 1, wherein the first alignment mark is defined by disposing the first metal film surrounding a position of the first alignment mark, and the second alignment mark is defined by disposing the second metal film surrounding a position of the second alignment mark.
 9. The light emitting device according to claim 8, wherein the base member further includes a second surface positioned higher than the first surface with the second surface surrounding the first surface in a top view, the second surface including a narrow portion and a wide portion having a greater width than the narrow portion, the first metal film and the second metal film are disposed on the wide portion of the second surface.
 10. The light emitting device according to claim 1, wherein the one or more electrical components include a temperature measuring element.
 11. The light emitting device according to claim 1, wherein the first semiconductor laser element is electrically connected to the first meal film and the second metal film.
 12. The light emitting device according to claim 1, wherein the first semiconductor laser element and the second semiconductor laser element are electrically connected to the first meal film and the second metal film.
 13. The light emitting device according to claim 1, wherein the plurality of metal films further include a third metal film electrically connected to at least one of the one or more electrical components, and the third metal film does not define an alignment mark.
 14. The light emitting device according to claim 1, wherein the first semiconductor laser element is configured to emit blue light. 